ECONOMICAL GEOLOGY. 
311 
No. 1 is from the Whitehurst pump. 
No. 2 is from Manly’s pump. 
No. 3 is from the Gildersleeve pump. 
No. 4 is from the Episcopal Church pump. 
No. 5 is from the Lane pump. 
No. 6 is from H. J. B. Clark’s, 9 miles from Newbern. 
No. 7 is from T. S. Howard’s, 1^ miles north of Newbern. 
It will be observed that the solid matter about reaches the limit of pota- 
bility in two cases. These are the second and fourth. And it will also be 
obserbed that much of the excess in both cases is common salt, (chlorine 
and sodium), which exists in much greater proportion in these wells 
than in any of the others. This is explained by the fact that they both 
penetrate to a level below the surface of the Neuse River, whose waters 
are brackish, and the former is only 200 feet distant from it. These 
waters also contain a larger proportion of lime and organic matter than 
the others. Their temperature is also highest, indicating a more direct 
communication with waters having the surface temperature, so that 
they cannot be recommended as wholesome drinking water, although 
they are within the allowed limits of potability. The quantity of silica 
found in all these waters is very considerable ; but there is nothing 
specially injurious to health in this mineral, beyond the fact that it is so 
much added solid matter . The organic matter is also large in all of the 
samples, and in several of them, notably so. The Whitehurst, for ex- 
ample, comes next to the Episcopal Church well in this respect. This is 
doubtless due to the source of the water, which is to be sought in the 
peaty swamps and rivers further inland, from which these waters are de- 
rived through their communication with the subterraneous streams. A 
considerable additional part of the solid matter of this water is evidently 
derived from the river, as indicated by the large proportion of chlorine, 
sodium and magnesia. The temperature of this well shows, however, 
as well as its structure, that the main sources of its supplies are distant 
and deep, — that they are a part of the subterraneous circulation peculiar 
to this section, and arising from its special geological features, explained 
elsewhere. 
Of course those wells are the safest sources of water for drinking and 
other domestic uses, which reach this underground circulation, provided 
of course they do not also communicate with brackish or other undrinka- 
ble waters. The shallower wells, — those which stop short of this stra- 
tum, that is, which derive their supplies directly from the rainfall by per- 
colation through the superficial porous, sandy strata, which characterize 
